Nested sector gears

ABSTRACT

A sector gear is formed as one of a pair of mirror image gears ( 12, 14 ). Each of the sector gears has an arcuate portion ( 16 ) having a series of teeth ( 18 ) on an outer periphery thereof, and a V-shaped base portion ( 20 ) having a first leg ( 22 ), a second leg ( 24 ) and an apex portion ( 26 ). The first leg ( 22 ) has an S-shaped configuration and connects with the arcuate portion ( 16 ) at a first end thereof. The second leg ( 24 ) has an inverted S-shape and connects with the arcuate portion ( 16 ) near an arcuate mid-length of the arcuate portion ( 16 ). The first leg ( 22 ) and second leg ( 24 ) merge smoothly with the apex portion ( 26 ). The apex portion ( 26 ) has an aperture ( 30 ) at a radial center of the arcuate portion ( 16 ). Each of the gears has an inner periphery ( 28 ) that enables complementary nesting of the pair of sector gears ( 12, 14 ).

FIELD OF INVENTION

[0001] This invention relates to a method for producing sector gears andthe sector gears made therefrom.

BACKGROUND OF INVENTION

[0002] Window regulators on vehicles commonly employ sector gears inorder to reduce the effort required to open and close a window. Theprior art sectors gears are “pie slice” shaped. The outer curved edgedhas a series of teeth, while the narrow end has an aperture defining thecenter of rotation of the gear. The intermediate portion between theouter periphery and the center of rotation is often removed in order toreduce weight of the sector gear.

[0003] The prior art sector gears are stamped from sheet metal. If thesector gear has an angle of about 45°, a plurality of sector gears canbe stamped in an alternating fashion in order to reduce scrap. However,the intermediate portion must still be stamped out and discarded orrecycling.

[0004] If the sector gear has an angle of greater than 45° (FIG. 3), thesector gears cannot be arranged in an efficient manner. The size ofsheet metal required to stamp a single gear is approximately the lengthof the longest dimension by the narrow dimension. The corners and theintermediate portions are discarded or recycled.

SUMMARY OF INVENTION

[0005] The disadvantages of the prior art may be overcome by providing asector gear having a configuration which enables high density nesting tominimize scrap, yet maintain strength and performance characteristics.

[0006] According to one aspect of the invention, there is provided asector gear formed as one of a pair of mirror image sector gears. Eachof the sector gears has an arcuate portion having a series of teeth onan outer periphery thereof, and a V-shaped base portion having a firstleg, a second leg and an apex portion. The first leg has an S-shapedconfiguration and connects with the arctuate portion at a first endthereof. The second leg has an inverted S-shape and connects with thearcuate portion near an arcuate mid-length of the arcuate portion. Thefirst leg and second leg merge smoothly with the apex portion. The apexportion has an aperture at a radial center of the arcuate portion. Eachof the gears has an inner periphery that enables complementary nestingof the pair of sector gears

[0007] According to another aspect of the invention, the degree ofnesting of the nested pair of sector gears can be controlled by thedegree of curvature of the second leg of the base portion.

DESCRIPTION OF THE DRAWINGS

[0008] Drawings which illustrate the present invention, in which:

[0009]FIG. 1 is a plan view of a pair of nested sector gears of a firstembodiment the present invention,

[0010]FIG. 2 is a plan view of a pair of nested sector gears of a secondembodiment of the present invention; and

[0011]FIG. 3 is a plan view of a sector gear of the prior art.

DESCRIPTION OF THE PRESENT INVENTION

[0012] Referring to FIG. 1, there is illustrated a pair of nested sectorgears 12, 14 of the present invention. The sector gears 12, 14 aremirror images of each other and formed in an inverted back to backrelation.

[0013] Sector gear 12 has an arcuate portion 16. The outer periphery ofthe arcuate portion 16 has a series of teeth 18.

[0014] A V-shaped base portion 20 is integrally connected to the arcuateportion 16. Base portion 20 has a first leg 22, a second leg 24 and anapex 26. First leg 22 preferably has an S-shaped configuration extendingfrom an end region of the arcuate portion 16. The first leg 22 mergessmoothly with the apex 26. The second leg has an S-shaped configuration,inverted relative to the S-shaped configuration of first leg 22. Thesecond leg 24 extends from approximately the circumferential mid-lengthof the arcuate portion 16 and merges smoothly with the apex 26.

[0015] The inner periphery 28 of the base portion 20 is configured tonest with a like periphery in an inverted back to back relation asillustrated.

[0016] The apex 26 has an aperture 30 which is located at the radialcenter of the arcuate portion 16. There is an imaginary line 32extending from the radial center of aperture 30 to the circumferentialmid-length of the arcuate portion 16. Second leg 24 will extendarcuately away from this line 32. In the preferred embodiment, the line32 of one of the sector gears 12, 14 will extend generally parallel toeach other.

[0017] Referring to FIG. 2, a second embodiment of the present inventionis illustrated. The nested pair of sector gears 42, 44 are identical tothe nested pair of sector gears 12, 14, except that the second leg 50has a more pronounced curvature than second leg 24. By increasing thecurvature, a higher degree of nesting and therefore material efficiencycan be achieved.

[0018] In comparison with a conventional sector gear 60, as illustratedin FIG. 3, a pair of nested sector gears can be stamped from an area ofsheet of material slightly larger than the area occupied by the priorart sector gear 60. The nested pair of sector gears provides about 36%savings in material and approximately a reduction of about 3% in weight.Surprisingly, the sector gears 12, 14 of the present invention arecapable of carrying loads comparable with the conventional sector gear60.

[0019] In the preferred embodiment, the nested pair of sector gears arestamped from sheet material, preferably 3.22 mm sheet steel. However,other materials known in the art may also be used.

[0020] The above-described embodiment of the invention is intended to bean example of the present invention and alterations and modificationsmay be effected thereto, by those of skill in the art, without departingfrom the scope of the invention as defined in the attached claims.

What is claimed:
 1. A sector gear formed as one of a pair of mirrorimage gears, each of said gears comprising an arcuate portion having aseries of teeth on an outer periphery thereof, and a V-shaped baseportion having an apex portion, said apex portion having an aperture ata radial center of said arcuate portion, said gears being contoured tonest with each other as said pair are formed.
 2. A sector gear asclaimed in claim 1, wherein each of said gears has an inner peripherydefined by said base portion and an inner edge of said arcuate portion,said inner periphery of one of said pair of gears complementarily nestswithin the inner periphery of the other of said pair of gears.
 3. Asector gear as claimed in claim 2 wherein said base portion has a firstleg and a second leg, said first leg connecting with said arctuateportion at a first end region thereof, said second leg connecting withsaid arcuate portion near an arcuate mid-length of said arcuate portion,and said first and second legs connecting with each other defining saidapex portion.
 4. A sector gear as claimed in claim 3 wherein said firstleg has an S-shaped configuration and said second leg had an invertedS-shape.
 5. A sector gear as claimed in claim 4 wherein said gears arestamped from a single sheet material in a nested condition.
 6. A sectorgear as claimed in claim 5 wherein said sheet material is steel.